The present invention relates to a medical packaging material. More particularly, the present invention relates to a medical packaging material which may be sterilized by an oxidizing gas plasma, such as a hydrogen peroxide plasma.
Cellulosic sheets and cellulose-polymer reinforced composites are widely used as medical packaging materials for lidding and pouching applications, among others. Medical packages typically enclose medical instruments, devices, and apparel and protect them from the external environment. Because such items are sterilized within the packages by such processes as autoclaving, ethylene oxide, radiation, hydrogen peroxide, and the like, the packaging material must be permeable to the sterilizing agent. However, there is one sterilization process with which cellulose-based materials generally are incompatible, i.e., a hydrogen peroxide plasma-based method such as that used in Advanced Sterilization Products' STERRAD.RTM. 100 Sterilization System (Advanced Sterilization Products, Irvine, Calif.). At the present time, only polypropylene- and polyethylene-based nonwoven materials, such as Tyvek.RTM. (E. I. DuPont de Nemours, Wilmington, Del.), are appropriate packaging materials for sterilization in the STERRAD.RTM. unit. Cellulose-based materials appear to absorb hydrogen peroxide, reducing the amount of peroxide available in the chamber for sterilizing. This results in a concomitant decrease in the pressure in the sterilization chamber which causes the abortion of the sterilization cycle and prevents sterilization of the chamber's contents.
Once the STERRAD.RTM. unit is loaded with packages to be sterilized, a vacuum is created in the sterilization chamber and a fixed amount of hydrogen peroxide is injected into the chamber and allowed to diffuse throughout the chamber and into the packages. It is in this injection stage that abortion of the cycle due to the presence of cellulose is most likely to occur. More specifically, abortion occurs when the pressure in the chamber does not equal or exceed 6.0 torr. This lack of sufficient pressure is an indication that there is not enough sterilant (hydrogen peroxide) in the chamber to adequately sterilize the chamber's contents.
Thus, there is an opportunity for a less expensive alternative to the polyolefin-based nonwoven materials mentioned above, thereby providing medical personnel with a choice of packaging materials for use in the STERRAD.RTM. sterilization unit or other oxidizing gas plasma systems.